Ladder construction



Oct. 20, 1953 w, SHARRQCK 2,656,087

LADDER CONSTRUCTION Filed April 4, 1952 2 Sheets-Sheet l INVENTOR.

mam fllzarroc/o,

Oct. 20, 1953 w. SHARROCK 2,656,087

LADDER CONSTRUCTION Filed April 4, 1952 2 Sheets-Sheet 2 IN V EN TOR.

77:12am J/zarra 0/6, BY

Patented Oct. 20, 1953 UNITED TES TENT OFFIQE LADDER CONSTRUCTIONWilliam Sharrock, Beverly, Mass.

Application April 4. 1952, Serial No. 280,543

2 Claims. 1

The present invention relates to ladder constructions and moreparticularly to an improved rung assembly therefor.

Among the objects of the present invention is to provide an improvedrung for ladders which is characterized by its increased strength,economical cost, ease of installation and its ability to strengthen andreinforce the ladder to an extent which permits its use in supportingheavy staging without danger of failure.

Another object of the present invention is to provide an improved rungof such a construction that ladders may be sold in knock-down conditionand readily assembled by the purchaser.

The present invention contemplates a novel rung assembly for ladderswhich is in the form of a replacement unit for use in substitution ofold rungs of ladders which have become worn to the point of being unsafeor completely unusable because of structural failure.

More particularly the invention comprehends a rung assembly asimmediately hereinabove described which may be readily and easilysubstituted as a replacement rung for the rungs of the conventional typeladder without disassembling the same.

Still another object of the present invention is to provide an improvedrung assembly of multipart construction in which the parts are formed insuch a manner as to assure proper resistance to heavy loads and in whichthe same are interlocked with the side rails of the ladder to preventthe side rails from spreading apart and to greatly reduce lateralswaying of the ladder.

Other objects, features, capabilities and advantages are comprehended bythe invention as will later app-ear and as are inherently possessedthereby.

The present application is a continuation in part of application SerialNo. 100,347, filed June 21, 1949, now abandoned.

Referring to the drawings:

Figure l is a plan view of a ladder embodying the present invention;

Figure 2 is an enlarged fragmentary view in elevation of a section of aladder embodying an improved rung assembly made in accordance with thepresent invention, parts thereof being shown in section to disclose thestructure more in detail;

Figure 3 is an enlarged fragmentary view in end elevation of thestructure shown in Figure 2 of the drawings;

Figure 4 is an enlarged view partly in section and partly in elevationof the end flange for the rung positioning member;

Figure 5' is an enlarged fragmentary view in section disclosin analternative form of construction for the rung assembly made inaccordance with the present invention;

Figure 6 is an enlarged fragmentary view in end elevation of thestructure shown in Figure 5 of the drawings;

Figure 7 is a cross-sectional view taken in the plane represented byline l'? of Figure 5 of the drawings;

Figure 8 is an enlarged sectional view of the rung assembly shown inFigure 2 of the drawings and disclosing more particularly a step inassembling the same with the side rails of a ladder;

Figure 9 is a view similar to Figure 8 of the drawings disclosing therelation of the parts of the rung as the assembly thereof progresses;

Figure 10 is an enlarged fragmentary front view of a ladder showing afurther modified rung constructicn therefor;

Figure 11 is an enlarged fragmentary vertical cross-sectional viewshowing the rung construction for the ladder shown in Figure 10 of thedrawings;

Figure 12 is an enlarged fragmentary end view of the ladder shown inFigure 10 of the drawings; and

Figure 13 is a viewin cross section taken in the plane represented byline [3-43 of Figure 11 of the drawings.

Referring now more in detail to the drawings, one form of rung assemblymade in accordance with the present invention and particularly adaptedfor use as a replacement part for a ladder as shown in Figure 1 of thedrawings is disclosed as comprising an outer sheath 2 of a lengthdefined by the distance between the inner faces of the side rails 4 and6, a core 8, and a rail securing member iii. The core 8 is of a lengthcorresponding to the distance between the outer faces of the rails t and6 and the same is mounted adjacent its ends in the openings l2 and M ofthe rails i and 6, respectively. The rail securing member is in the formof a metal tie rod, non-circular in cross-section and having laterallyextending flanges I6 and i=8 at the ends thereof adapted to engage theouter faces of the rails 4 and 6, respectively, for positioning theserails and interlocking the rung assembly therewith.- The flanges I6 andI8 have their inner faces spaced apart a distance for proper alignmentof the rails 4 and 6 and are formed with teeth 2!! thereon adapted toimbed themselves in the rails 4 and 8 to prevent the tie member Hi fromturning relative to the rails. The tie member Ill throughout its lengthis received Within the radial groove 22 formed in the periphery of thecore 8 which positions the core 8 and prevents rotation thereof relativeto the member ID and the rails 4 and 6. The outer sheath 2 is disposedin substantial end abutting relation with the inner face of each of therails 4 and 6, thus serving as a spacing element for the rails. Thisouter sheath completely embraces and encloses the core 8 and the tiemember ID to provide a complete rung assembly for the ladder.

During the assembling of the rung in a ladder an adhesive orcementitious material may be applied to the periphery of the core 8and/or the. inner surface of the outer sheath 2 which is. adapted toharden or set for holding the outer sheath against rotation relative to.the core 8 and to hold the core 8 against lateral displace.- ment withrespect to the rails 4 and 6. Any other suitable securing means may beprovided for effectin this unitary type of structure whereby the partsof the rung assembly are positioned with respect to the rails.

The present invention contemplates an im proved type of rung assemblywhich lends itself to the production of ladders for sale in knockdowncondition, which may be readily assembled by the purchaser. Theembodiment of the invention disclosed in Figures 2, 3 and 4 may be usedin this type of ladder construction, but in a new ladder, theembodiments of the invention disclosed in Figures 5-7 and -13 arepreferably used. The rung assembly disclosed in Figures 5-7 andidentified generally by the reference character 24 is of substantiallythe same construction as the rung assembly shown in Figures 2, 3 and 4of the drawings. In constructing a new ladder, however, it is relativelysimple procedure to form the rails 4 and 6 with recesses 26 extendinglaterally of the openings I2 and I4 and adapted to receive the laterallyextending flange 28 at the ends of the rod 39. These recesses are of adepth conformin to the thickness of the flanges 28 so that when theladder is completed in its final form, the said flanges are flush withthe outer surface of the rails 4 and 6.

The rung construction shown in Figures 10 to 13, inclusive, conforms ina good many respects to the embodiment shown in Figures 5, 6 and '7, andcomprises the rails 4 and 6, having the longitudinal securing member IDextending through the openings I2 and I4 therein and formed with theflanges 32 and 34 received in recesses, such as 36, provided in theouter faces of the rails '4 and 6. A core 38 is provided having a groove48' adapted to embrace the longitudinal securing member ID and which isenclosed by the sheath 42 having end abutting relation with the innerfaces of the rails 4 and 6. The sheath 42 is provided with a groove 44adapted to embrace the elongated securing or positioning member ID. Itwill thus be seen that when the elements of this modification areassembled in the manner hereinafter more fully described, the elementsare held in their assembled relation by virtue of the flanges 32 and 34which prevent outward bowing of the rail members 4 and '6, and by thesheath 42 which prevents inward movement of the rails with respect toone another. By providing the sheath 42' with the groove 44 whichembraces the elongated .positioning member ID, the sheath is preventedfrom rotating. Thus it will be seen that the use of adhesive which ispreferably used in the first two embodiments between the sheath and coreis eliminated.

The present invention contemplates the use of at least one of the railassemblies herein disclosed adjacent each end of the ladder of theknockdown type, it being understood that the remaining rungs may be ofthe conventional type. The present improved rung assemblies are used totie the entire ladder assembly together as a unitary structure, althoughthe invention is of such scope as to comprehend the use of rungs of thetype herein disclosed throughout the length of the ladder.

The ease and facility with which these rung assemblies may be insertedin place as, for example, a substitute for a worn or broken rung in aconventional type ladder, reference may be made to- Figures 8 and 9which show a rung assembly of the type shown in Figures 2, 3 and 4 ofthe drawings, although the manner of assembling the form shown inFigures 5, 6 and 7, and 10-13 is identical. In assembling the rung, the,outer sheath 2- is first positioned between the rails 4 and 6, afterwhich the tie rod II] is inserted through one of the openings I2 or I4of the rails through the outer sheath 2 and through the oppositelydisposed opening of the opposite rail. The end flanges I6 and I 8 arethen positioned with respect to the rails 4 and 6 with the tie memberII] in engagement with the walls forming the openings I2 and I4, as moreparticularly shown in Figure 8 of the drawings. The'core 8 is theninserted into one of the openings I2 or I4 of the side rails asillustrated in Figure 8 so that the recess 22 is in alignment with therod [0 after which, the sheath 2 is properly aligned with the openingsI2 and I4 as the core 8 is moved transversely with respect to the rails.This introduction of the core 8 within the outer shaft 2 is illustratedin Figure 9 of the drawings which shows the core in its intermediateposition. The core 8 is then moved laterally or transversely withrespect to the railsuntil such time as the ends are in alignment withthe outer faces of said rails. In the assembly of the ladder rung shownin Figures 10-13, it is of course understood that the grooves of boththe core and outer sheath must be properly aligned with respect to themember. As indicated above, a permanent unitary structure may be formedby applying adhesive or cementitious material between the core 8 and theouter sheath of the embodiments shown in Figures 2, 3 and 4 and Figures5, 6 and '7 whereby the assembly is fixed in position with respect, tothe side rails 4 and 6. In the embodiment shown in Figures 10 to 13,however, the groove in the sheath prevents rotation thereof and,accordingly, no adhesive is necessary.

It will be apparent that the improved rung as herein disclosed may bereadily and easily assembled with respect to the side rails as areplacement for worn or broken rungs of the conventional type. Such rungassembly is of such a construction as to withstand the loads imposedthereon by heavy staging and the same is securely interlocked with theside rails to prevent excessive swaying of the'ladder and to preventoutward spreading of the rails 4 and 6, thus lending itself admirably tosuch use as a substitute or replacement part, although as hereinaboveset forth, the invention contemplates the use of such assembly inmanufacturing ladders of the knock-down type.

While I have herein described and upon the drawings shown illustrativeembodiments of the invention, it is to be understood that the inventionis not limited thereto but may comprehend other constructions,arrangements of parts, details and features without departing from thespirit thereof.

It is claimed:

1. In a ladder, the combination of opposed side rails provided withtransversely disposed substantially aligned openings, a rung, said rungcomprising an outer sheath disposed between said Side rails with itsends abuttin the inner faces of the rails, an elongated memberinsertable into assembled relation with said side rails through at leastone of said openings and said outer sheath and having laterallyextending flanges at the ends thereof having shouldered engagement withsaid side rails at the outside face to hold the same in proper spacedaligned relation and holding said member against rotation relativethereto, and a core having an elongated groove insertable into assembledrelation with said side rails through at least one of said openings andsaid outer sheath when said groove is aligned with said elongatedmember, the ends of the core extending into the openings in both rails.

2. In a ladder, the combination of opposed side rails provided withtransversely disposed substantially aligned openings, a rung, said rungcomprising an outer sheath disposed between said side rails with itsends abutting the inner faces of the rails, said sheath having aninternal lon- 30 gated member fitting into the internal groove of thesheath member, and a core having an elongated groove insertable intoassembled relation with said side rails through at least one of saidopenings and said outer sheath when said groove is aligned with saidelongated member, the ends of the core extending into the openings inboth rails.

WILLIAM SHARROCK.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 640,645 Fall Jan. 2, 1900 1,051,275 Schreiner Jan. 21, 19131,461,952 Walchi July 17, 1923 FOREIGN PATENTS Number Country Date336,888 Great Britain Oct. 23, 1930 501,557 Great Britain Mar. 1, 1939

